1. Field of Invention
The present invention relates to a semiconductor structure and a method of forming the same.
2. Description of Related Art
As the level of integration of a semiconductor device, such as a memory device, is getting higher, the dimension of the same is getting smaller. In the photolithography process, it is known that raising a line or space resolution beyond 65 nm, especially a line/space width of less than 50/50 nm, in the current state of technology is rather difficult, unless a light source having a shorter wavelength and a corresponding photoresist are used. However, it is very costly to replace existing machines entirely with new machines for this purpose.
Accordingly, how to reduce a line/space width to less than 50 nm/50 nm with existing machines and processes has become an important topic in the industry.